Mama is a 4th Grader

Natsumi Mizuki is a fourth-grader whose parents have moved to London, leaving her in the care of her aunt, Izumi. Izumi is an aspiring manga artist struggling to land her first big break, so she isn't thrilled when a baby mysteriously appears on Natsumi's first night alone. The baby, named Mirai, turns out to be Natsumi's own daughter-from 15 years in the future. Now, young Natsumi has to juggle raising Mirai, keeping her fourth-grade life from unraveling, and hiding Mirai's existence from everyone around her. She gets some questionable assistance from Izumi and a few futuristic baby gadgets, but it's still far from easy.